As will be apparent from pages 384-388 of "Principles of Automotive Vehicles", U.S. Government Printing Office, Washington, D.C., 1978, road wheels of a track-laying vehicle are provided between the chassis and the resilient suspension and are the members which ride upon the track as it is continuously laid down by the movement of the vehicle over the terrain.
Consequently, the road wheels serve to transmit the ground pressure from the chain to the chassis via the suspension and to support the weight of the chassis and the vehicle on the track and the ground.
For high speed track-laying vehicles, e.g. those used for military purposes, the configuration of the road wheel is especially important because it determines the handling characteristics of the vehicle and the wear characteristics which are significant. The road wheels are subjected to considerable stress in addition to wear. In general such road wheels can be assembled from wheel halves, e.g. by bolting them together, the two wheel halves defining between them an outwardly open groove into which the teeth of the track project.
Because it is important to keep the unsuspended mass of the vehicle as small as possible to avoid vibration and the like, in order to allow high speeds, the weight of the wheels is an important factor and should be minimized. However, it must be borne in mind that the friction stresses, especially in the regions in which the teeth engage into the wheel are significant and that the wheels must also be capable of withstanding attack by explosives or projectiles.
Thus there are a number of mutually contradictory or conflicting requirements for such wheels. In order to minimize the weight of the road wheels of track-laying vehicles, it has been proposed to form the wheel halves of aluminum. To minimize the wear in the tooth-engaging regions of the wheel, the wheel was provided in the region of a channel with wear-resisting rings of high strength steel (see German patent document DE-AS No. 19 39 240). However, such wheels did not fulfill all requirements, since they were prone to attack by incendiary or explosive means, the aluminum wheels readily melting or even burning upon such attack.
Steel wheels can overcome the latter disadvantage and thus are proposed in German patent document DE-AS No. 12 01 693. These wheels are provided with wear-resisting regions of polyamide synthetic resins where wear is paramount as in the locations at which the teeth of the track penetrate into the wheel channel. However, such steel wheels are comparatively heavy.